Arron is really the silent type, but then he could also be the player type. Which in the manga Rui is.

Akira is the player out of all the F4, since most fan like Chun, he's good for the role.

Calvin . . . well he's like a player but he knows what that are important. like Soujiroh.

Hebe looks pretty with short and long hair just like Makino is the Manga. I can image her tough but I can't image her playing the role very well.

Great casting =D. No offense to anyone, but Chun should definitely be reduced to a supporting role, his acting is far from being good. And does who honestly thinks he can pull off Domyouji's dumb snob role? Snob maybe, but dumb no.

Doumyouji Tsukasa: Jiro (just an outrageous guy can definitely play the hothead role)
Hanazawa Rui: Arron (already seems like the quiet type that cares)
Mimasaki Akira: Calvin (looks like can do the playboy role and look like a crazy good fighter)
Nishikado Soujiroh: Wu Chun (very calm quiet cool seems like the type to do that while making tea)

Makino Tsukushi: Genie (for some reason i just like her at this moment in time b/c she has been in dramas with all of them except Arron so the chemistry should be there)
Matsuoka Yuuki: Angela (looked alright with wu chun in romantic princess)

and of course a fahrenheit drama with jiro you can not forget Danson however i actually dont remember anymore guy roles except for makino's little brother but his role is hardly seen in the drama

and the b****y of the mom should be played by the lady from bullfighting cause she's the only one i can think of

and maybe the really pretty model rui chases after should be played by rainie since like gossip swirled around her and arron however she has to be older and i would like to see hebe in the drama too so maybe hebe should play that role

*added* hey it just hit me that the sakurabo or ba something like that should be played by ella